1. Field of the Invention
The present invention relates to a process for producing a cationic polymer emulsion. More particularly, it relates to a process for producing a cationic polymer emulsion which has both mechanical and chemical stability without the use of conventional emulsifiers.
2. Description of the Prior Art
In the manufacture of synthetic rubbers, synthetic resins and paints, aqueous emulsion polymerization using an emulsifier has been employed to produce the polymer. However, emulsifiers discharged in process waste waters are a source of water pollution. In preparing adhesive agents, the use of solvents has been limited because they are a source of air pollution. Also, it is often difficult to use the conventional solvent-type adhesive, and it is preferable to use an emulsion-type adhesive instead.
In emulsions produced by the conventional emulsion polymerization using an emulsifier and in polymers separated from such emulsions, emulsifier remains and interferes with subsequent use of the product. For example, the retained emulsifier causes the adhesion of the polymer onto mixing rolls and molds. It is also known that the retained emulsifier causes separation of the phases of adhesive compositions and reduces the adhesive property of the emulsion.
It has been theorized that these difficulties result from the separation of the emulsifier from the polymer particles under certain conditions because the emulsifier is physically adsorbed on the surface of the polymer particles in the emulsion. In order to overcome these difficulties, it has been proposed to produce an emulsion by using an unsaturated acid or a reactive emulsifier without using conventional emulsifiers in the case of an anionic emulsion. (Japanese Unexamined Patent Publications Nos. 34588/1974 and 40388/1974). However, no known technique exists for preparing a cationic emulsion.
Accordingly, there exists a need for a process capable of preparing cationic polymer emulsions without the use of conventional emulsifiers.